Syracuse

C rimean-Congo hemorrhagic fever (CCHF) is a se- vere zoonotic disease endemic in various regions of Europe, Asia, and Africa, including the Balkans, central Asia, and sub-Saharan Africa (1). The disease is caused by the CCHF virus (CCHFV), which is predominantly maintained and transmitted by Hyalomma spp. ticks. However, the virus also can be transmitted to humans through direct contact with the bodily fluids of infected animals and humans (2). In 2023, CCHF reemerged in North Macedonia (3; D. Jakimovski et al., unpub. data, https://doi.org/10.21203/rs.3.rs-4360716/v1), having been absent for >50 years since a 1970 outbreak. The combined mortality rate for the 1970 and 2023 outbreaks was 18.75% (3/16 cases) (4; D. Jakimovski et al., unpub. data). In response to this escalating public health concern in the Balkan Region (D. Jakimovski et al., unpub. data), the Balkan Association for Vector-Borne Diseases implemented a strategic plan emphasizing clinical vigilance and capacity sharing. Those efforts culminated in the detection and characterization of an autochthonous CCHFV strain linked to the 2023 outbreak (D. Jakimovski et al., unpub. data). Our study explored the reemergence of CCHF cases in North Macedonia, emphasizing the co-circulation of multiple autochthonous viral strains.

On April 26, 2024, a man in his 60s (case-patient 1) with no notable medical history was admitted to the Clinic for Infectious Diseases in Skopje (CIDS), Skopje, North Macedonia. He resided alone in a rural village in the northeastern region of North Macedonia in the municipality of Kriva Palanka (Figure 1). He worked as a self-employed herder and had not traveled outside the region in the preceding month. On April 14, 2024, the patient noticed a tick attached on his left lower leg and removed it with tweezers. The exposure site was ≈17 km south of the border with Serbia and ≈15 km east of the border with Bulgaria (Figure 1). Seven days after tick removal (day 0), the patient had malaise and persistent nosebleeds, which continued despite nasal tamponade. On day 4, he noticed dark stools, prompting a visit to an internal medicine specialist. Laboratory tests revealed leucopenia, thrombocytopenia, and elevated aminotransferase levels (Appendix 1,